This R21 proposal is in response to NOT-MH-12-001, the US-Russia Bilateral Collaborative Research Partnerships (CRP) on the Prevention and Treatment of HIV/AIDS and Co-morbidities. The proposed study will gather information about HIV testing utilization and influences on HIV testing decisions among young, general population Russian women at-risk of HIV exposure. The study will compare HIV testing acceptance across two types of low-barrier testing strategies (opt-in vs. opt-out) and will conduct one of the first randomized experimental comparisons of these strategies. HIV testing is a key element of HIV transmission prevention that is particularly salient for women in the general population. The study will make innovative use of focus groups to gather qualitative data and to determine if participation in peer discussion may lead to reconsideration of testing decisions among testing non-acceptors. The overarching goal is to gain knowledge that can be used to increase utilization of HIV testing among at-risk young women in Russia and offer urgently needed gender- specific strategies for improving prevention. The proposal builds on an established collaborative research program between the University of Oklahoma Health Sciences Center (OUHSC) and St. Petersburg State University (SPSU). Study aims include: (1) estimating HIV risk prevalence, attitudes, beliefs, and barriers that influence testing decisions; (2) experimentally comparing opt-in vs. opt-out HIV testing strategies and exploring subpopulation moderating effects; (3) estimating the number of testing non-acceptors who might accept testing after peer discussion about testing in a focus group; and (4) based on the information obtained in aims 1-3, developing a strategy for increasing HIV testing and risk reduction among young Russian women. To our knowledge, this project will be among the first that focuses on sexually active young Russian women in the general population to identify gender-specific HIV risk and prevention strategies, reduce HIV transmission, and experimentally compare opt-in vs. opt-out testing strategies. The study will provide critical information about the role of testing barriers, testing presentation, and peer influence on HIV testing decisions, which can be used to engineer and refine public health strategies.